1. Field of the Invention
The present invention relates to dumbbells and relates more particularly to a dumbbell which can be conveniently adjusted to change its weight.
2. Description of Prior Art
A dumbbell generally has a short bar of wood or iron with heavy ends, used in exercising the arms. This structure of dumbbell has a fixed total weight once it was made. Because the total weight is not adjustable, different dumbbells may have to be used by different persons according to respective amount of exercise. There is disclosed a weight adjustable dumbbell which can be adjusted to change the weight according to different requirements. This structure of weight adjustable dumbbell, as shown in FIG. 1, is generally comprised of a short bar A having a plurality of pin holes A1 symmetrically spaced on two opposite ends thereof for releasably fastening different pairs of round weights by lock pins. This structure of weight adjustable dumbbell is still not satisfactory in use. One disadvantage of this structure of weight adjustable dumbbell is that the round weights may oscillate on the two opposite ends of the short bar as it is lifted or swung about in the hand for muscular exercise, causing a balancing problem. Another disadvantage of this structure of weight adjustable dumbbell is that the lock pins may disconnect from the short bar or be broken easily causing the round weights to suddenly displace from respective positions or drop from the short bar, and therefore an exercising accident may happen easily.